An optical imaging device is known from EP 1 020 751 B1, in which the outer mount and the inner mount, adjustable in reference thereto, are preferably made in one piece, i.e., monolithically. A manipulator device, serving to displace an optic element mounted in a displacement-controlled fashion in the inner ring in a direction perpendicular in reference to the optical axis comprises a system of circumferential cutouts (recesses) between the inner ring and the outer mount, which form interposed connecting members, a rotary joint, and at least one adjusting joint with an adjusting member.
The disadvantage of this solution particularly comprises that it shows a complicated and asymmetrical design due to a plurality of differently shaped manipulator units, here called manipulator elements, which is unsuitable for symmetric systems or leads to system instabilities. In particular, the connecting members, acting as reinforcements in the direction of the optical axis but unnecessary cinematically, increase the production expenses, require additional actuators depending on their number, and cause deformations having a greater effect upon the inner part. Additionally, the adjusting joints require a separate flat spring and must be adjusted to ensure the intended adjustment in two opposite directions such that pre-stressing elements are necessary for both directions.
In DE 100 51 706 A1, a version is also disclosed which is divided by several cutouts into an inner mount and an outer mount, which remain connected between the cutouts, With these connections representing manipulator units in the sense of the invention. The cutouts are located such that via an activation of the connections by engaging manipulators, the inner mount and thus the lens held can be axially displaced and thus it represents no radially displaceable mount comparable to the one in the invention.
From DE 10 062 786 A1 a monolithically produced lens mount is known, decoupled from deformation, which here is divided by cutouts, called the annular gap, into an outer mount ring and an inner mount ring,
The annular gap is interrupted several times by narrow connecting bars, here called solid joints. By extending the annular gap in the radial and tangential directions at the solid joints, they assume an L-shape, comprising a radially aligned outer bar section and a tangentially aligned inner bar section.
Sensors and actuators are arranged in form of films at the solid joints, each extending opposite over the length of the solid joints. Any oscillations and/or deformations detected by the sensors are forwarded via a computer to the actuators, which create counter oscillations and/or counter deformations.
Using a lens mount decoupled from deformations, no adjustment of any lens held in the inner mount ring is possible in reference to the outer mount ring, thus it cannot relate to a mount for a radial adjustment of a mounted lens.
DE 10 2006 060 088 A1 discloses a monolithic lens mount, here called mounting, in which radially elastic bars are embodied, with their foot ends contacting a mounted lens. This lens mount can compensate for differences in the expansion of the lens and the lens mounting due to fluctuating temperatures, however a mounted lens cannot be adjusted radially.
WO 2006/119970 A2 relates not to a monolithic optical mount, but to a mount comprising an assembly made from an inner mount ring and an outer mount ring, which are connected directly via connecting elements, comprising flat springs each connected to each other via bars, here called small bridges.
Another lens mount made in one piece and therefore being monolithic is known from EP 1 577 693 A2. In a preferred embodiment an inner ring is connected to an outer mount via three manipulator units, here called adjusting joints, having two hinged brackets each and an adjustment part located in between. Actuators engage the adjusting joints for a lateral adjustment of the inner ring and thus the optical element.
Compared to the abovementioned DE 100 51 706 A1, the solution disclosed here is characterized by a higher temperature stability.
As explained in EP 1 577 693 A2, during the heating of the optical element, e.g., a lens, the problem arises that the it is difficult for heat to dissipate via the few and narrow connection points between the inner ring and the outer mount. The temperature differences developing thereby have disadvantageous effects upon the imaging quality, because particularly a longitudinal change of the hinged brackets extending in the same direction leads to a displacement of the inner ring in said direction due to temperature changes, which results in aberrations and coma.
This problem is attained in a lens mount according to EP 1 577 693 A2 essentially such that the hinged brackets engage, off-set in reference to each other in the tangential direction by 120°, at the outer circumferential area of the inner ring and at the inner circumferential area of the outer mount in the clock-wise direction away from the inner ring. A longitudinal change of the hinged brackets is here converted into a uniform direction of distortion. Distortions of this kind lead not to any aberrations, particularly not if lenses are the optical elements.
A lens mount according to EP 1 577 693 A2 is also said to be advantageous in that a higher lateral stiffness of the inner ring connection can be achieved by shortening the hinged brackets and thus the lens mount with the mounted lens is stiffer in reference to internal oscillations. A higher lateral stiffness by shortening the hinged brackets is achieved at the expense of the sensitivity of the adjustment, which not only concerns the length of the members but also the extend of the hinged brackets bending.
The length of the hinged brackets is here still predetermined by the tolerable material stress. This means when in a predetermined adjustment path and predetermined sensitivity the tolerable material stress limit is reached then no further shortening of the joints is possible to increase stiffness and/or resonance frequency. Consequently, always two relatively thin and, compared to the cross-section relatively long hinged brackets are necessary to implement the function as an adjustment unit and/or joint, which generally restricts the lateral and axial stillness achievable.
In DE 10 2007 030 579 A1, a first embodiment for a laterally adjustable lens mount is described, in which it is essentially equivalent to one according to EP 1 577 693 A2, i.e., three manipulator units arranged off-set by 120° in reference to each other are each embodied as members, which at their stationary ends transfer into two tangentially aligned hinged brackets, here called bars, which are connected to the inner mount part and/or the outer mount part.
In second embodiment the bars connecting the member to the inner and/or outer mount part are aligned radially, thus achieving higher lateral stiffness.
A deflecting of the lever, by introducing a radially acting force at the free end of the lever via a manipulator, leads to far higher tensile forces in the radial bars in reference to the tangential bars, though. The development of undesired tensions in the inner ring is unavoidable here.
In both embodiments, the manipulator units are simple lever gears, with their transmission being determined by the length of the member and the bending of the bars in the radial direction. In order to yield high sensitivity with an appropriate adjustment travel the bars and/or hinged brackets are embodied tong, which may lead to distortions in the axial direction.
In all abovementioned monolithic mounts the manipulator units are intentionally designed in their geometry and dimension such that they allow sensitive adjustments and a high adjustment stability, achieved as independent as possible from mechanical and thermal stress. The manipulator units, which represent the units by which an inner radially displaceable mount ring is connected to an outer stationary mount ring and by which a displacement of the inner mount ring is introduced in reference to the outer mount ring, are lever gears in the broadest sense according to prior art.
Lever gears have the purpose of transmitting or converting a path or a force. In the case of optical mounts, a distance shall be reduced generally in order to displace the mounted optical element as sensitively and therefore precisely as possible.
In order to produce a monolithic mount with manipulator units formed by lever gears, cutouts must be milled particularly embodied by material cutouts.
For this purpose, electro-erosive methods are generally used, such as wire eroding, by which very fine cutouts can be achieved. This way, on the one hand very small cutouts can be cut into the width of the separating cutouts and on the other hand cutouts of an arbitrary width, by aligning the cutouts along the circumference, wider than the cutting width.
The highly precise production of such mounts as well as the sensitive adjustability of an optical element in this mount is particularly opposed by high production costs due to the use of electro-erosive methods, which then seem unjustified if there are no higher requirements on the precision for the adjustment of such an optical element held in the mount.